Start 'Em & Sit 'Em is the ultimate look at the weekly NFL matchups and how they'll affect your fantasy football team. Sleeper alert features an under-the-radar player who could produce good numbers. Owners beware features a regular fantasy starter who could fail to meet expectations based on the strength of his opponent. Obvious fantasy starters like Aaron Rodgers and Arian Foster will not be featured in this column. For your final lineup decisions, check our lineup rankings.

Start of the week

Seahawks defense vs. Arizona Cardinals: If you have the Seahawks defense on your 2012 fantasy roster, consider it a must start this weekend. Teams had been feasting on the Cardinals offense (or lack thereof) and Ryan Lindley, scoring a combined 46 fantasy points over the last three weeks. I don't think the return of John Skelton makes this matchup any less favorable.

Start 'em

Browns defense vs. Kansas City Chiefs: While this unit has been inconsistent overall, the Browns still have a pretty respectable defense from a fantasy perspective. In fact, I'd start them against the Chiefs in what is a very favorable matchup. Opposing home defenses that have faced this offense have combined to score the second-most fantasy points this season.

Buccaneers defense vs. Philadelphia Eagles: The Buccaneers don't have an elite defense from a fantasy perspective, but it's tough not to love this week's matchup against the Eagles. With rookie Nick Foles under center and limited offensive options, this team has been one to target in the defensive matchups in recent weeks. The Bucs are available in most leagues.

Sleeper alert - Jaguars defense vs. New York Jets: If you have watched the Jets on offense this season, you know exactly why I have the Jaguars listed as a sleeper. Opposing defenses have combined to score the fourth-most fantasy points against the Men in Green this season, and that's with Mark Sanchez at quarterback. He'll remain the starter this weekend too.

Sit of the week

Texans defense at New England Patriots (Mon.): The Texans defense is coming off a huge fantasy performance, scoring 22 points in a win over the Tennessee Titans. However, a similar stat line can't be expected against the Patriots on Monday night. In fact, opposing defenses facing the Patriots in New England have averaged less than two fantasy points per game.

Sit 'em

Cardinals defense at Seattle Seahawks: Like the Texans, the Cardinals are coming off a huge fantasy line in Week 13. And, like Houston, this week's matchup is a whole lot tougher. Defenses that have faced Russell Wilson and the Seahawks in Seattle have combined to average fewer than five fantasy points per game, so look elsewhere for a defensive solution.

Top 10 Targets for Week 13

Eagles defense at Tampa Bay Buccaneers: What has happened to the Eagles? In less than two seasons, this unit has gone from being projected as a top fantasy defense to becoming an absolute mess. There's no break in sight, either, as Philadelphia faces a Buccaneers offense next on the schedule that has not been a good matchup for opposing defenses this season.

Owners beware - Ravens defense at Washington Redskins: Despite all of their injuries, the Ravens have still remained a nice fantasy option this season. Still, facing Robert Griffin III on the road is not an attractive matchup. In fact, opposing defenses that have faced the Skins have combined to score the fifth-fewest fantasy points at the position overall in 2012.